There are numerous applications that require flow meters. Increasingly mass flow meters are necessary. Some mass flow meters make use of exciters. Prior art exciters are generally formed with a frame that is fixed on a pipe and a coil that is fixed on an adjacent pipe. Only one electromagnet is used. When there is a current in the coil, it causes a magnetic field.
In the prior art designs, there are a number of problems. For example, under high frequency vibration, the exciter core will heat up. This creates a potential risk of coil burnout. Also, because there is a small gap between the core and coil, a problem can arise if and when the core and coil come in contact. Such contact may change the natural frequency of the prior art unit and affect its accuracy. Furthermore, the core's weight and the coil frame weight must be controlled; specifically, they must both be the same. If this careful balance is not struck, the vibration may be unbalanced which can cause the whole mass flow meter to be unbalanced.
Therefore, there is a need in the art for an exciter with better performance that can be adjusted to fit and match specific design requirements.